An assembly for use in a liquid droplet apparatus

ABSTRACT

An assembly for use in a liquid droplet apparatus comprises a vibrating element ( 201 ), an aperture plate ( 205 ) and a vibrating platform ( 203 ). The vibrating platform is positioned between the vibrating element and the aperture plate for conveying vibrations from the vibrating element to the aperture plate. The vibrating platform ( 203 ) is structured such that the aperture plate ( 205 ) is located within a cavity ( 202 ) formed in the vibrating platform.

TECHNICAL FIELD

The invention relates to an assembly for use in a liquid dropletapparatus for producing liquid droplets, for example for use inultrasonic mesh aerosol nebulizer devices, and in particular to anassembly such as a mesh sub-assembly.

BACKGROUND

Aerosol generators are used in various industries to produce finedroplets. For example, nebulisers deliver pharmaceuticals in dropletform, for example for inhalation.

There are many known nebuliser designs, which include human and springpowered devices. Much recent research has been directed to the use ofelectrically powered nebulizers, for example jet nebulisers (also calledatomizers), which force a gas through a liquid containing the medicine,ultrasonic wave nebulisers, in which a piezoelectric element vibrates acolumn of liquid to produce a vapour mist, and vibrating meshtechnology, in which an aperture plate is vibrated against the surfaceof a liquid reservoir, or has a supply of liquid supplied directly tothe aperture plate. The aperture plate may comprise a mesh, a screen, amembrane, a machined metal plate, a polymer or the like, having manytiny openings or micro nozzles. When the aperture plate is vibrated(usually by a piezoelectric element), fine droplets are dispensed.

Nebulizers of this type comprise a mesh sub-assembly, often in the formof a ring, in which an aperture plate (such as a screen, mesh, membrane,machine metal plate, polymer or the like, as mentioned above) is coupledto a vibrating source (such as a piezoelectric element).

Previous ring style mesh aerosol systems are described with a surfaceisland and a three dimensional structure that protrudes from a mountingplate, or as a single piece structure in which the mesh is permanentlyattached to the vibrating structure. Ring style mesh aerosolarrangements of this type are formed with the mesh being attached to theexternal surface or top of the island.

FIG. 1 shows a mesh sub-assembly in which a aperture plate 105 iscoupled to a vibrating platform 103, using as a non-limitative examplean adhesive 107. The vibrating platform 103 couples the aperture plate105 with a vibrating element 101 (such as a piezoelectric ring element).The vibrating platform 103 acts to transmit vibrations received from thevibrating element 101 to the aperture plate 105. The arrow shows thedirection of spray during use, based on liquid being applied to theaperture plate 105 is a corresponding direction. During use, contractionof the vibrating element 101 in an inward radial direction causes theangled structure to become less angled or less sloped, i.e. moreorthogonal to a plane in which the vibrating element 101 lies, thuscausing the aperture plate 105 to move in a forward direction, that istowards the bottom of the page in the Figure, or in the direction ofspray as shown by the arrow in FIG. 1.

As can be seen from FIG. 1, in such an arrangement the aperture plate105 protrudes from the assembly. This has a disadvantage of requiringadditional space. Furthermore, the aperture plate 105 is susceptible tobeing inadvertently dislodged or removed.

SUMMARY

It is an aim of the present invention to provide an apparatus or methodwhich obviates or reduces at least one or more of the disadvantagesmentioned above.

According to a first aspect of the present invention there is providedan assembly for use in a liquid droplet apparatus. The assemblycomprises a vibrating element, an aperture plate and a vibratingplatform. The vibrating platform is positioned between the vibratingelement and the aperture plate, for conveying vibrations from thevibrating element to the aperture plate. The vibrating platform isstructured such that the aperture plate is located within a cavityformed in the vibrating platform.

This has the advantage of protecting the aperture plate from accidentaldislodgement from the vibrating platform. This structure also has theadvantage of reducing the overall height of the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of examples of the present invention, and toshow more clearly how the examples may be carried into effect, referencewill now be made, by way of example only, to the following drawings inwhich:

FIG. 1 shows a known sub-assembly;

FIG. 2 shows an embodiment of the present invention;

DETAILED DESCRIPTION

Preliminary, it should be clearly understood that in the meaning of theinvention the terms “vibrating element” and “vibrating platform” equallydesignate or be construed as an element and a platform that areconfigured to vibrate, respectively. It should further be clear that inthe meaning of the invention any vibration related to this element ofplatform should occur during use only.

FIG. 2 shows a cross-sectional view and a plan view of an assemblyaccording to an embodiment of the present invention, for use in a liquiddroplet apparatus.

The assembly comprises a vibrating element 201, an aperture plate 205and a vibrating platform 203. The vibrating platform 203 is positionedbetween the vibrating element 201 and the aperture plate 205 forconveying vibrations from the vibrating element 201 to the apertureplate 205. The vibrating platform 203 is structured such that theaperture plate 205 is located within a cavity 202 formed in thevibrating platform 203.

In the example of FIG. 2 the vibrating element 201 takes the form of anannular vibrating element, for example an annular piezoelectric device,also known as a piezoelectric ring, wherein during use the annularpiezoelectric device is radially expandable and contractable uponactuation thereof, i.e. vibrates in a radial direction. The annularpiezoelectric device also vibrates in an axial direction.

The aperture plate 205 may comprise, for example, a mesh, a screen, amembrane, a machined metal plate (for example involving electroformingand laser ablation), a polymer or the like, having many tiny openings ormicro nozzles. For example, the aperture plate 205 may be flat as shown,or domed in shape.

The embodiment of FIG. 2 has the advantage of protecting the apertureplate 205 from accidental dislodgement from the vibrating platform (bythe manner in which it is located within a cavity 202 formed by thevibrating platform 203).

In the example of FIG. 2 the vibrating platform 203, having the apertureplate 205 arranged within a cavity 202 thereof, is structured such thata sidewall 203 c of the vibrating platform (coupling a first annularportion 203 a and a second annular portion 203 b) protrudes at leastpartly through the opening in the annular vibrating element 201. Thishas the further advantage of reducing the overall height of theassembly.

The assembly of FIG. 2 is therefore effectively inverted compared to thestructure of FIG. 1, with the vibrating platform 203 being attached, inthis example, to the vibrating element 201 on a side corresponding tothe direction of spray. In such an example, movement of the apertureplate in a direction of the spray (referred to herein as a “forward”direction) is caused by expansion of the vibrating element in anoutwardly radial direction, rather than by contraction in an inwardlyradial direction as required in FIG. 1.

It is noted that, if desired, the direction of spray can be reversed inFIG. 2 by changing the direction in which liquid is applied to theaperture plate, for example such that the direction of liquid anddirection of spray are opposite to that shown in FIG. 2. In such anembodiment a “forward” movement of the aperture plate 205 is obtained bycontraction of the vibrating element 201 in an inwardly radialdirection, similar to that of FIG. 1.

In FIGS. 2 to 3, the first annular portion 203 a of the vibratingplatform can be fixedly coupled to an annular portion of the vibratingelement 201, and the second annular portion 203 b can be fixedly coupledto the aperture plate 205.

For example, the aperture plate 205 may be coupled to the vibratingplatform 203 using adhesive 207, and the first portion 203 a of thevibrating platform may be fixedly connected to the vibrating element 201using an adhesive (not shown).

The embodiments of the present invention allow the aperture platecomponent 205 to vibrate in direction “A” when the annular piezoelectricelement expands outward in a radial direction, in contrast totraditional mesh ring style aerosol generators which rely on the inwardradial movement to provide a compression force to the mesh in order tovibrate in direction “A”, which can also be termed a “forward”direction. The forward direction action allows fluid to be transmittedfrom the back side surface to the micro nozzles to the front surface asa spray. The embodiments of the present invention can therefore operateeffectively in reverse compared to a conventional device, i.e. radialexpansion rather than contraction of the annular piezoelectric devicecauses a forward movement of the aperture plate 205 in direction “A”.This has the advantage of requiring less power to deliver a higheroutput rate of aerosol.

The inward cone or cavity defined by the embodiments of the inventionprovides a means of a built in barrier to prevent accidental removal ofthe aperture plate 205, for example protecting the aperture plate frombeing inadvertently removed from the adhesive which affixes the apertureplate to the vibrating platform 203.

The vibrating platform 203 may comprise at least one flexible joint (forexample a joint which is non-stressed during manufacture), for allowingadditional movement of the vibrating platform in response to movement ofthe vibrating element in a radial direction. This allows for additionalmovement (amplitude)”, in a similar manner as a speaker when more poweris added. Thus, having a flexible joint enables a greater amplitude ofmovement to be obtained for a given power that is applied to thepiezoelectric device. This has the advantage of being able to increasethe amplitude of movement without having to necessarily increase thepower applied to the piezoelectric device, which can have power savingadvantages, in addition to preventing damage to the piezoelectricdevice.

The geometry related to the inward facing structure that expands in theoutward radial motion of a ring style piezo vibrator, provides theadvantages of being able to move the aperture plate in response toradial movement of the vibrating element, and also protect the apertureplate within the cavity formed by the inward facing structure.

According to one embodiment the vibrating platform comprises a firstsurface for coupling to a vibrating element, and a second surface forcoupling to an aperture plate, the plane of the first surface beingseparated from the plane of the second surface by sidewalls that couplethe first and second surface.

The sidewalls define a cavity. The aperture plate is located within thecavity, on a side of the second surface which is inward facing to thecavity.

The embodiments of the invention can be applied to any form ofrespiratory drug delivery apparatus, including a nebulizer or atomizer.Applications include, for example, respiratory care or sleep assistancenebulizer for delivery for home humidification via nasal cannula ormask.

The embodiments of the invention can be used to support efforts in homehealth care solutions as a part of a liquid nebulizer drug deliverysystem, or a humidification system for critical or home ventilation orsleep or nasal cannula via oxygen.

The embodiments of the invention provide an improved ultrasonic meshaerosol nebulizer, in which the mesh sub-assembly is equal or lower thana piezo ring assembly.

It is noted that, in any of the embodiments described above, theaperture plate can take other shapes or forms, for example in additionto the flat or domed shapes described herein.

According to one embodiment there is provided an assembly for use in aliquid droplet apparatus. The assembly comprises a vibrating element, anaperture plate and a vibrating platform for coupling the vibratingelement and the aperture plate. The vibrating platform is structuredsuch that the aperture plate is positioned within a conical structureformed by the vibrating platform.

According to another embodiment there is provided an assembly for use ina liquid droplet apparatus. The assembly comprises a vibrating element,an aperture plate and a vibrating platform for coupling the vibratingelement and the aperture plate. The vibrating platform is formed from aninverted structure, such that the aperture plate is positioned within aconical structure formed by the vibrating platform.

The sidewalls of the vibrating platform may be angled with respect to aplane of the vibrating element, and wherein expansion of the vibratingelement in an outwardly radial direction causes the sidewalls of thevibrating platform to become more orthogonal with respect to the planeof the vibrating element, thereby causing the aperture plate to move ina forward direction.

The vibrating platform may be circular in shape, and comprise a firstsurface for coupling to the vibrating element, and a second surface forcoupling to the aperture plate, the plane of the first surface beingseparated from the plane of the second surface by a sidewall thatcouples the first and second surfaces.

The aperture plate may be located within the cavity, on a side of thesecond surface which is inward facing to the cavity.

The sidewall may be angled with respect to the plane of the vibratingelement. In such an embodiment, the angle of the sidewall is adjustedthrough contraction and expansion of the vibrating element in a radialdirection in the plane of the vibrating element.

The vibrating platform may comprise a joint which is non-stressed duringmanufacture, for allowing additional movement of the vibrating platformin response to movement of the vibrating element in a radial direction.

Although the examples show the diameter of the annular vibrating element201 being larger than the diameter of the first annular portion 203 a ofthe vibrating platform 203, it is noted that the diameter of the annularvibrating element 201 may be smaller than, or equal to, the diameter ofthe first annular portion 203 a of the vibrating platform 203, withoutdeparting from the scope of the invention as defined in the appendedclaims.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. The word “comprising” does not excludethe presence of elements or steps other than those listed in a claim,“a” or “an” does not exclude a plurality, and a single processor orother unit may fulfil the functions of several units recited in theclaims. Any reference signs in the claims shall not be construed so asto limit their scope.

1. An assembly for use in a liquid droplet apparatus, the assemblycomprising: a vibrating element; an aperture plate; and a vibratingplatform; wherein the vibrating platform is positioned between thevibrating element and the aperture plate for conveying vibrations fromthe vibrating element to the aperture plate, wherein the vibratingplatform comprises a first annular portion for coupling to the vibratingelement, a second annular portion for coupling to the aperture plate,and a sidewall to define a cavity; wherein the first annular portionlies in a first plane and the second annular portion lies in a secondplane, the second plane being separated from and substantially inparallel with the first plane, and separated from and substantially inparallel with a third plane corresponding to a plane in which thevibrating element lies, wherein the sidewall protrudes at least partlythrough an aperture of the vibrating element, and wherein the vibratingplatform is structured such that the aperture plate is located within acavity formed in the vibrating platform.
 2. An assembly as claimed inclaim 1, wherein the vibrating element comprises an annularpiezoelectric device, wherein during use the annular piezoelectricdevice is radially expandable and contractable upon actuation thereof.3. (canceled)
 4. An assembly as claimed in claim 1, wherein theSidewall, of the vibrating platform is angled with respect to the firstand second planes of the vibrating platform, and configured such thatany expansion of the vibrating element during use in a radially outwarddirection causes the sidewall of the vibrating platform to become lessorthogonal with respect to the first and second planes of the vibratingelement, thereby causing the aperture plate to move, during use, in adirection corresponding to a direction of spray.
 5. An assembly asclaimed in claim 1, wherein the first annular portion of the vibratingplatform is fixedly coupled to an annular portion of the vibratingelement, and the second annular portion fixedly coupled to the apertureplate.
 6. An assembly as claimed in claim 1, wherein the vibratingplatform is configured such that the sidewall of the vibrating platformpasses through an aperture in the vibrating element.
 7. An assembly asclaimed in claim 5, wherein the aperture plate is located within thecavity such that the aperture plate is coupled to a side of the secondannular portion which is inward facing to the cavity.
 8. An assembly asclaimed in claim 1, wherein the vibrating platform is structured suchthat the aperture plate is positioned within a cavity comprising aconical structure formed by the vibrating platform.
 9. An assembly asclaimed in claim 1, wherein the vibrating platform is formed from aninverted structure, such that the aperture plate is positioned within aconical structure formed by the vibrating platform.
 10. An assembly asclaimed in claim 1, wherein the first annular portion of the vibratingelement is fixed to the annular piezoelectric device on a sidecorresponding to a direction of flow of a fluid during use, and whereinthe sidewall and second annular portion of the vibrating element projectat least into the aperture of the annular piezoelectric device in adirection opposite to the direction of flow.
 11. An assembly as claimedin claim 1, wherein the vibrating platform comprises a joint which isnon-stressed during manufacture, for allowing additional movement of thevibrating platform, during use, in response to movement of the vibratingelement in a radial direction.
 12. An assembly as claimed in claim 1,wherein the vibrating platform comprises at least one flexible joint.13. An assembly as claimed in claim 1, wherein the vibrating platform isstructured such that one or more intersections between the first annularportion 203 a, second annular portion 203 b and sidewall 203 c arecurved.